There are a wide variety of tools designed for picking up objects or manipulating objects from a distance. One common application for such tools is use by maintenance workers to pick-up debris for subsequent disposal. A tool with an elongate handle allows manipulation of the object without the need to bend over or to directly handle the material. Such tools are also useful for individuals that have physical handicaps that may impede their ability to bend over and reach the ground. There are also numerous household applications for such tools including retrieval of materials from high shelves or from under furniture. Another common application for such tools is for changing light bulbs from recessed lighting fixtures. Another entire class of devices that operate in a similar manner and perform a similar function as the pick-up tools described above are marketed as toys. Other tools may have blades on the distal end for cutting that may be used for a wide range of uses including those tools used in the surgical field and tools used for trimming high branches.
Common elements that are shared by such devices that are addressed by the improvement disclosed herein include (1) an elongate shaft having (2) a handle on one end and, (3) engagement elements on the opposite end, (4) a controller element on the handle and (5) a linkage from the controller element to the engagement elements. The user of the these tools may manipulate a controller, such as a lever or trigger, that is provided on the handle end of the device to operate the engagement elements that are provided on the opposite end of the elongate shaft. The engagement elements may include arrangements such as claws, arms, scoops, calipers, tongs, blades or cups. In typical designs, the control lever pulls an internal linkage that draws together the engagement elements that are biased apart by springs.
Exemplary arrangements of such devices are disclosed in the U.S. Pat. No. 4,962,957 (the “'957 Patent”), U.S. Pat. No. 4,709,839 (the “'839 Patent”), U.S. Pat. No. 3,527,492 (the “'492 Patent”), U.S. Pat. No. 4,613,179 (The '179 Patent), U.S. Pat. No. 4,669,769 (the '769 Patent) and U.S. Pat. No. 6,257,634 (the '634 Patent).
A desirable feature that is sometimes incorporated on these devices is a locking mechanism that enables the engagement elements to be retained in a fixed position. A locking features allows a user of the device to retain the engagement elements in a closed position and in contact with an object and thereby allow a user to release pressure on the controller while maintaining control over the object. Consequently, a user can use his or her free hand to further manipulate the object, either directly, or indirectly by using the elongate shaft. Allowing the user to release pressure on the controller yet maintain engagement of the object also adds a convenience feature.
There have been a number of alternative manners to accomplish locking engagement elements on grabber tools that are disclosed in the prior art. For example, the patent to Moyer, U.S. Pat. No. 1,120,735, discloses a segment that can be manipulated by a lever that in turn may be secured in place by a pawl. The pawl is biased against the ratchet segment by a leaf spring. The '957 patent discloses an alternative manner in which to lock the engagement elements of a pick-up tool that allows the trigger to be released while maintaining pressure on the object. U.S. Pat. No. 5,823,590 to Forrest et al. discloses yet another alternative method of locking the engagement elements thereby allows a user to manually secure the central linkage in fixed position. U.S. Pat. No. 6,438,891 to Aboczky provides a spring locking mechanism.
While, there exist numerous types of devices and a variety of alternative manners in which to lock engagement elements in fixed positions, many of the efforts disclosed in the prior art have involved fairly complex arrangements and require multiple parts. In general, increased complexity of a proposed device is associated with increased expense in connection with manufacturing and with respect to the costs of the parts required to achieve the feature. Accordingly, there continues to remain a demand and a commercial market for devices that have a simple and inexpensive locking arrangement. A further desirable feature to provide with elongate engagement tools is the ability for the device to fold or collapse. Because these devices employ an elongate rod, the devices are somewhat cumbersome in connection with shipping, handling, display and storage. While it is desirable to provide a manner in which to collapse the device, the manner in which the collapse is affected must accommodate the linkage between the controller and engagement elements and must also maintain sufficient strength to support objects when the elongate member is in an extended position. While the prior art has recognized this need, there remains room for improved alternative and effective manners to achieve these goals. In this regard, for example, U.S. Pat. No. 4,613,179 relies upon a stop pin 71 that is designed to work only when the device is in an upright position. U.S. Pat. No. 5,823,590 discloses a telescopic arrangement to collapse a grabber device. U.S. Pat. No. 4,231,603 discloses a grabber device with a hinge fixture that allows the proximal and distal ends of an elongate rod to be aligned in different directions.
It is an object of the present invention to provide a new locking arrangement for the engagement elements of a pick-up tool that is simple to manufacture and assemble and that uses only a few parts. A further object of the present invention is to provide an engagement device that has a locking device that can be easily manipulated by the user. A further objective of the invention is to provide a locking hinge on the elongate arm or rod that allows the devices to fold yet maintain strength when in an extended position.